Table 1 Baseline characteristics of patients at initiation of anti-tumour necrosis factor (TNF) therapy
Disease characteristicsAnti-TNF agents with MTX (n = 842)Anti-TNF agents with LEF (n = 260)Anti-TNF agents with other DMARDs (n = 116)p Value*
Age, years53 (14)53 (13)55 (15)0.23
Median disease duration, years8.4 (IQR: 3.7–14.9)8.9 (IQR: 3.3–14.2)9.9 (IQR: 4.4–15.8)0.14
Female, %7679780.57
Rheumatoid factor positive, %8083830.60
DAS284.1 (1.5)4.5 (1.4)4.6 (1.4)0.31
RADAI4.3 (2.1)4.5 (2.2)4.2 (2.1)0.43
Functional disability (HAQ)1.24 (0.71)1.34 (0.67)1.33 (0.72)0.54
Median erosion score, % of maximum†6.3 (IQR: 2.0–17.3)5.8 (IQR: 2.1–17.6)6.3 (IQR: 2.7–17.3)0.85
Type of anti-TNF:
Adalimumab, %3341280.02
Etanercept, %3132450.01
Infliximab, %3627270.01
Previous anti-TNF failure, ever, %33%41%36%0.06
Concomitant steroid-use, ever, %48%51%67%0.001
Median* of previous DMARDs, n1 (IQR: 0–2)2 (IQR: 1–3)2 (IQR: 1–3)<0.001
  • Values are given in mean (SD) if not indicated otherwise. When not normally distributed, the medians and interquartile ranges (IQR) of the variable are reported. Steroid use  =  concomitant use of oral glucocorticoids at any time during anti-TNF therapy. Erosion score based on the Ratingen scoring method; semi-quantitative scale estimating the proportion of destroyed joint surface in 38 hands and feet joints, expressed as percent of maximum score.

  • *One-way analysis of variance (ANOVA) of means normally distributed continuous variables; Kruskal–Wallis test for non-normally distributed variables; χ2 test for dichotomous variables.

  • †The total number of patients with a full set of radiographs available for scoring at baseline was lower: n = 859 instead of n = 1218.

  • DAS28, Disease Activity Score based on 28 joints, higher scores indicate more disease activity; DMARD, disease-modifying antirheumatic drug; HAQ, Health Assessment Questionnaire, higher scores indicate more disability; LEF, leflunomide; MTX, methotrexate; RADAI, Rheumatoid Arthritis Disease Activity Index, higher scores indicate more disease activity.